diff --git a/ext/SymbolicsLuxExt.jl b/ext/SymbolicsLuxExt.jl
index b4dfcab51..60e748950 100644
--- a/ext/SymbolicsLuxExt.jl
+++ b/ext/SymbolicsLuxExt.jl
@@ -5,13 +5,15 @@ using Symbolics
 using Lux.LuxCore
 using Symbolics.SymbolicUtils
 
-function Lux.NilSizePropagation.recursively_nillify(x::SymbolicUtils.BasicSymbolic{<:Vector{<:Real}})
-    Lux.NilSizePropagation.recursively_nillify(Symbolics.wrap(x))
+@static if isdefined(Lux.NilSizePropagation, :recursively_nillify)
+    function Lux.NilSizePropagation.recursively_nillify(x::SymbolicUtils.BasicSymbolic{<:Vector{<:Real}})
+        Lux.NilSizePropagation.recursively_nillify(Symbolics.wrap(x))
+    end
 end
 
 @register_array_symbolic LuxCore.stateless_apply(
     model::LuxCore.AbstractLuxLayer, x::AbstractArray, ps::Union{NamedTuple, <:AbstractVector}) begin
-    size = LuxCore.outputsize(model, x, LuxCore.Random.default_rng())
+    size = LuxCore.outputsize(model, Symbolics.wrap(x), LuxCore.Random.default_rng())
     eltype = Real
 end
 
diff --git a/src/utils.jl b/src/utils.jl
index 5fffae8a5..17d91a971 100644
--- a/src/utils.jl
+++ b/src/utils.jl
@@ -62,7 +62,7 @@ function is_singleton(e)
         op = operation(e)
         op === getindex && return true
         iscall(op) && return is_singleton(op) # recurse to reach getindex for array element variables
-        return issym(op)
+        return issym(op) && !hasmetadata(e, CallWithParent)
     else
         return issym(e)
     end
@@ -76,6 +76,7 @@ function get_variables!(vars, e::Symbolic, varlist=nothing)
             push!(vars, e)
         end
     else
+        get_variables!(vars, operation(e), varlist)
         foreach(x -> get_variables!(vars, x, varlist), arguments(e))
     end
     return (vars isa AbstractVector) ? unique!(vars) : vars
diff --git a/test/utils.jl b/test/utils.jl
index 727c53366..709024da5 100644
--- a/test/utils.jl
+++ b/test/utils.jl
@@ -19,6 +19,14 @@ using Symbolics: symbolic_to_float, var_from_nested_derivative, unwrap
 
     sorted_vars2 = Symbolics.get_variables(ex2; sort = true)
     @test isequal(sorted_vars2, [x, y])
+
+    @variables c(..)
+    ex3 = c(x) + c(t) - c(c(t) + y)
+    vars3 = Symbolics.get_variables(ex3)
+    @test length(vars3) == 4
+
+    sorted_vars3 = Symbolics.get_variables(ex3; sort = true)
+    @test isequal(sorted_vars3, [c.f, t, x, y])
 end
 
 @testset "symbolic_to_float" begin